High efficiency hydraulic apparatus



Oct. 10, 1967 J. TOBIAS 3,345,916

HIGH EFFICIENCY HYDRAULIC APPARATUS Filed Nov. 17, 1965 2 Sheets-Sheet 1 ATTORNEY Oct. 10, 1967 J. TOBIAS HIGH EFFICIENCY HYDRAULIC APPARATUS 2 Sheets-Sheet 2 Filed Nov. 17, 1965 m Q MM 7 W M 3 m Q E Q Q m M A W v l km W I mm ll. mm n NW II' \III l ,r} U I z m Ev QV Nfi /m m W\ hm kw QM A Ii mm w k P I m w wwl/ J ww /H/ 7 N ATTORNEY United States Patent 3,345,916 HIGH EFFICIENCY HYDRAULIC APPARATUS Jaromir Tobias, Box 141, RD. 2, Rhiuebeck, N.Y. 12572 Filed Nov. 17, 1965, Ser. No. 508,249 11 Claims. (Cl. 9258) ABSTRACT OF THE DISCLOSURE A high efficiency hydraulic pump or motor of the type in which a cylinder block having radially extending cylinder bores rotates about a central pintle shaft and wherein hydraulic fluid communicates from the pintle shaft to the cylinder bores through passages extending radially inwardly from the bores to an axial aperture in the block in communication with the pintle shaft discharge, said passages being characterized by the axial dimension of such passages at their radial innermost ends being in excess of the diameter of the cylinder bores and the transverse extent of said radial innermost ends being less than the diameter of said bores, said transverse and axial dimensions, respectively, increasing and decreasing as said passages approach said cylinder bores.

This invention relates to a hydraulic device, and more particularly to a hydraulic pump or motor device of the radial piston type. i

More particularly, this invention relates to an ultra high efficiency radial piston hydraulic pump or mot-or.

Still more particularly, this invention relates to an improved hydraulic pump or motor device of the type in which a block containing radial cylinder bores rotates about a pintle shaft having side discharge areas, the combination having improved conduits communicating between the pintle shaft and the cylinder bores, to increase the operating efiiciency of the device without any material increase in the size or weight of the pump or motor.

It is known to provide a hydraulic pump or motor wherein the cylinder block containing an odd number of radially extending cylinder bores rotates about and draws fluid from a plurality of ports formed on the lateral faces of the pintle shaft. The bores slidably receive piston memhere which oscillate radially within the bores under the influence either of an eccentric reaction ring bearing against the radial outward end portions of the pistons or, alternatively, by a cam track and follower connection between the pistons and some stationary component. i

All such pump and motor devices have heretofore been used primarily in special applications where the loss of efficiency experienced in their use has been more than ofiset by the special advantages which inhere in the use of hydraulic pump and motor systems.

More particularly, hydraulic systems are especially useful in that a single, infinitely variable hydraulic pump may, by appropriate connections, be utilized to drive one or more reversible hydraulic motors at positions remote from the pump, eachof the motors also being infinitely variable. However, as previously noted, due to the great power wastage inhering in the use of such hydraulic systems, their use in situations where high power applications are encountered has been heretofore considered impractical. As an example of an application known to be theoretically possible but heretofore considered impractical by reason of efiiciency losses may be noted the utilization of a single hydraulic pump to feed four hydraulic motors, each located at a different wheel of an automobile, for instance.

With the foregoing in mind, it is an object of the present invention to provide a high efficiency hydraulic pump or motor device.

A further object of the invention is to provide a novel hydraulic pump or motor of greatly improved efficiency by reason of a novel porting arrangement whereby the high losses heretofore inherent in hydraulic pumps and motors, occurring in the course of transfer of the fluid from the pintle shaft to the cylinder chamber, are obviated.

A further object of the invention is the provision of a hydraulic pump or motor device of the type described wherein the increase in efiiciency is achieved without significant increase in over-all size.

Briefly stated, the drastic increase in efliciency obtained through the use of my device is predicated upon the provision of passages within the cylinder block connecting the cylinder bores to the pintle shaft discharge area, the passages having a cross-sectional area approximately equal to the cross-sectional area of the cylinder chambers.

Ordinarily it might be expected that such an arrangement could be accomplished only through the use of a cylinder block of increased diameter and a pintle shaft of increased diameter, to permit the radial inner ends of the larger cross-sectioned passages to open onto the interior of the cylinder block without interference one with respect to the other. However, by the novel arrangement hereinafter described and claimed, the desired increased area passageways are provided without increasing the diameter of the block or the pintle shaft by, instead, elongating the axial dimension of the block at its junction with the pintle shaft. The passages leading from the pintle shaft to the cylinder chambers are axially elongated at the junction with the pintle shaft to exceed the diameter of the cylinder chambers. The transverse or lateral dimension of the passages at said junction is considerably less than the diameter of the cylinder chambers, such narrowed transverse dimension permitting the formation of a plurality of passages without any increase in the diameter of the pintle shaft discharge area or the block. By thus increasing the axial, and decreasing the transverse dimension, there are preferably defined passages which have a crosssectional area generally equal to the cross-sectional area of the cylinder bores. The axial extent of the passages progressively decreases and the transverse extent of the passages progressively increases at progressive, radially outwardly disposed portions of the passages, the radial uppermost end of the passages preferably merging smoothly into the cylinder bores. By thus increasing the transverse dimension, the cross-sectional area at all points of the passage is approximately equal to the cross-sectional area of the cylinder chambers.

From the foregoing it will be understood that the arrangement noted is adaptable for use in hydraulic pumps or motors of any type wherein radially moving pistons draw fluid from a pintle shaft, whether the outward and inward movement of said pistons is governed by an eccentrically disposed reaction ring, a cam and follower arrangement or any other means.

While the invention will be described in conjunction with a reaction ring type arrangement, it is not limited in its utility to such a ring.

To attain these objects and such further objects as FIGURE 4 is a section taken on the lines 44 of FIGURE 2;

FIGURE 5 is a perspective view of a solid geometric figure corresponding to the outline of the passages linking the cylinder bores to the pintle shaft, better to illustrate the shape of such passages.

Referring now to the drawings, there is illustrated a hydraulic pump or motor assembly 10, including a fixed frame 11 carrying a fixed, generally centrally disposed pintle shaft 12 which is mounted on fixed supports (not shown) carried by the frame. The frame 11 includes side wall portions 13 and 14, providing mounting means for the housing 15 of the hydraulic pump or motor.

As will be readily understood, the constructions of the pump and the motor are in all respects identical and, therefore, no distinction between these devices need be made.

The housing 15 may include laterally directed guide rods 16 and 17, integral with or separately attached to the housing. The guide rod 16 is slidably disposed within an aperture 18 formed in the side wall portion 14. An aperture 19 is formed within the side Wall portion 13. An adjustment wheel 20 is rotatably mounted within the aperture 19, the wheel 20 including an internally threaded boss 21. The guide rod 17 is externally threaded, as at 22, the boss 21 being complementally threaded over the portion 22.

Thus it will be evident that by rotation of the wheel 20, a lateral movement will be induced in the threaded portion 22 of the rod 17, to cause a lateral movement of the entire housing 15 between the walls 13 and 14.

It will be understood that the means for effecting the lateral adjustment of the housing shown in the illustrated embodiment is for purposes of exemplification only, and that other lateral shifting means may be employed. Similarly, as is well known, it is possible to maintain the housing in fixed position and obtain the necessary eccentricity by shifting the pintle shaft relative to the stationary housing.

The inner surface 25 of the housing 15 defines an annular raceway forming, in essence, one component of a roller bearing structure, an annular reaction ring 26, spaced from the surface 25 forming another component of the bearing. Between the reaction ring 26 and the annular surface 25 are disposed a plurality of cylindrical bearing members 27, which are maintained in spacedapart condition within the housing by the shallow, outwardly directed bearing sockets or recesses 28 formed in the outer surface of the reaction ring 26. Any suitable anti-friction means may be interposed between the housing and the ring where relative rotation between these parts is desired.

In certain applications it is not necessary to provide a rotating reaction ring, and in such instances the reaction ring may comprise a portion of the housing. Usually, in such devices the pistons carry rollers or like anti-friction devices.

Within the reaction ring 26 there is disposed a rotary block member 29 which is freely rotatably mounted for movement about the pintle shaft 12. The block 29, which is fixed against axial movement with respect to the pintle shaft, is provided with radially directed keyway slots 30, 31, providing a driving connection with the tubular drive shaft member 32.

The drive shaft member, which may be an output shaft in the case of a motor, or an input shaft in the case of a pump, includes a pair of axially directed teeth 33, 34, meshing respectively with the slots 30, 31, thus to. communicate rotary movement of the shaft to the block 29.

The block 29 incorporates the usual radially extending cylinder chambers 35. While the number of such chambers is not limited, it is common practice to provide an odd number, the illustrated embodiment incorporating nine.

The pintle shaft is hollowed to define axially extending input and output passageways 36, 37, respectively, the passageways terminating at their innermost ends in outwardly open discharge ports or chambers 38, 39, separated from each other by diametrically opposed lands L.

The block incorporates a central, axially extending bore or aperture 40 which is rotatably mounted over the pintle shaft. Preferably the block 29 is axially enlarged in the area adjoining the pintle shaft, the axial dimension of said block at the shaft preferably exceeding the axial dimension of the block at a point displaced from the shaft.

The axially elongated nature of the block in the area adjacent the shaft is sufficient to permit the block completely to span the length of the discharge ports or chambers 38, 39, the axial extremities 41, 42 of the bore portion 40 being, of course, completed annuli and forming sealing connections with the pintle shaft 12 in the unbroken cylindrical areas to either side of the discharge ports or chambers.

The block 29 incorporates a series of radially extending passages linking the cylinder bores with the central bearing aperture 49 of the block, to provide a fluid path between the ports or chambers 38, 39 of the pintle shaft and the cylinder bores.

It has been determined by me that an inherent source of efficiency loss in previously known hydraulic devices of this type lies in the inability of passages heretofore known to provide a full, free and uninterrupted communication between the pintle shaft and the cylinder bores. Thus, it is an important feature of the present invention that the passages remedy the deficiency noted. In order to accomplish this result without enlarging the over-all size, and particularly the diameter of the hydraulic pump or motor, the passages P of the present invention are axially elongated and transversely constricted at the portion of the block adjacent the bore 40.

As best seen in FIGURE 3, the passage P at said bore defines an elongated configuration in which the lengthwise dimension 50 exceeds the diameter 51 of the cylinder bores 35 by a considerable margin and the widthwise 0r transverse dimension 52 is less than the diameter 51 of the cylinder bore. Optionally but preferably, the total cross-sectional area of the passageway P at the bore 41) is equal or approximately equal to the cross-sectional area of a cylinder chamber 35.

In FIGURE 5, for purposes of illustration, there is shown a solid geometric configuration which approximates the preferred shape of the passage.

As best seen from FIGURES 1 and 5, the passages P taper angularly outwardly so as progressively to increase the transverse dimension of said passages as the passages approach the radial innermost ends of the cylinder bores 35. Similarly, as best seen in FIGURES 2 and 5, the axial dimension of the passages P is progressively reduced as the passages approach the radial innermost ends of the cylinder bores. Thus it will be seen that the outermost portions of the passages are preferably circular in section and the innermost portions comprise elongated, quasi-elliptical configurations.

It will be readily understood from the foregoing that the precise shape of the passages at the pintle-adjacent portion of the block may vary considerably, without departing from the spirit of the present invention. It is, however, an essential feature that said passages are axially elongated and transversely diminished at the pintleadjacent portion and converge axially and diverge transversely at progressive, radially disposed portions of the passages.

By the above disclosed arrangement, it is possible to provide a large number of cylinder bores without over-all size increase since, by reason of the fact that the passages are transversely diminished at the pintle-adjacent portion, a large number of such angularly-spaced-apart passages may open onto the bore without any mutual interference. Similarly, the transversely constricted nature of the passages at the bore does not diminish the cross-sectional area of the passages by reason of the elongated nature of the passages at the bore.

Each of the bores includes a piston member 55, the outermost ends 56 of which may be of domed or partispheroid configuration. The innermost ends 57 may be flat or, for improved suction purposes, may incorporate a concavity 58. The reaction ring 26 may be provided with an annular concave track 59, within which the domed portions 56 of the pistons may ride during the operation of the device.

Preferably, and in accordance with known practice, the angular extent of the lands L is approximately equal to or slightly exceeds the transverse dimension 52 of the passages at the pintle-adjacent portions thereof, the lands being disposed so that preferably only one of the passages is completely isolated from communication with the chambers 38, 39 at any one time.

The operation of the device is in all respects conventional and need not be elaborated upon. In general, where the device is used as a motor, hydraulic fluid under pressure is fed to one of the passages 36 or 37, the other of said passages communicating with the reservoir. The block will, in such case, be rotated and the drive shaft 32 may be connected to any device to be driven.

It will be recognized further that, in accordance with known principles, lateral adjustment of the housing 15, through the operation of the turn wheel 20 or any other suitable eccentricity inducing device, will vary the eccentricity of the reaction ring with respect to the rotating block and, thus, vary the stroke of the pistons, thereby controlling the torque and speed applied to the output shaft. Also in accordance with known principles, the operation of the eccentricity in an opposite direction will reverse the direction of rotation of the block.

When the device is to be used as a pump, a rotary force is applied to the input shaft 32, thus to forcibly rotate the block 29, causing hydraulic fluid from a reservoir to be sucked into one of the lines 36, 37, the other said line carrying the fluid under pressure.

From the foregoing it will be appreciated that there is provided a hydraulic pump or motor device of greatly increased efliciency, thus enabling devices of the hydraulic type to be substituted in applications heretofore considered uneconomical. Further, the highly desirable result is achieved without materially increasing the size of the device.

It will be readily recognized that the block may comprise an integral structure containing both the passage containing components and the cylinder bores. Alterna tively, and in some instances preferably, in order to facilitate the construction of the passages, it may be desirable to fabricate the block structure of two or more components, including an inner annulus containing the passages and an outer annulus containing the cylinder bores, the two being thereafter integrated into a fluidtight unit.

The illustrated embodiment discloses only one form of the invention and is included for purposes of compliance with the patent laws. Many variations and modifications of the illustrated embodiment may be made without departure from the spirit of the invention. Accordingly, the invention is to be broadly construed within the scope of the appended claims.

Having thus described the invention and illustrated its use, what is claimed as new and is desired to be secured by Letters Patent is:

1. In a rotary hydraulic device such as a pump or motor, a generally cylindrical pintle shaft having an axially elongated, recessed circumference portion defining a fluid supply area, a cylinder block having a central bearing aperturerotatably received on said shaft, the axial dimension of said aperture being in excess of the length of said recessed portion, said aperture being disposed in registry with said area, a plurality of radially extending cylinder bores formed in said block, and axially elongated fluid passages extending between said bores and said aperture, the axial dimension of said passages at said aperture being greater than the diameter of said bores, the transverse dimension of said passages at said boresbeing greater than the transverse dimension of said passages at said aperture.

2. A hydraulic device comprising a pintle shaft, circumferential fluid supply ports on said shaft, a cylinder block assembly having a central bearing aperture rotat ably mounted over said shaft, with said aperture overlying said supply ports, a plurality of angularly spacedapart, radially extending cylinder bores formed in said block assembly and radially extending fluid supply passages connecting said bores and said aperture, the area of any cross section through said passages taken perpendicular to the axis of said bores being substantially equal, the axial dimension of said passages at said aperture being greater than said dimension at said bore.

3. A device in accordance with claim 2 wherein said cross-sectional area of each of said passages is substantially equal to the total cross-sectional area of the piston bores fed by said passages.

4. In a hydraulic device of the type wherein a cylinder block having radial cylinder bores rotates about a pintle shaft, said shaft including circumferential fluid supply means, the improvement which comprises said fluid supply means being of a length in excess of the diameter of said bores and said block having fluid passages radially extending between said supply means and said bores, the upper end of said passages adjacent said bores being circular in section and of a diameter substantially equal to the diameter of said bores, the transverse and axial dimensions of sections through said passages, taken normal to the axis of said bores, respectively decreasing and increasing as said sections are taken respectively further from said bores.

5. In a hydraulic device of the radial piston type which includes a pintle shaft having a circumferential discharge area, the improvement which comprises a cylinder block having a central bearing aperture, a plurality of angularly-spaced-apart, radially extending cylinder bores and fluid passages connecting said aperture with said bores, the axial dimension of said passages at said aperture exceeding the transverse dimension of said passages at said aperture, said transverse dimension of said passages growing progressively larger and said axial dimension of said passages growing progressively smaller as said passages approach said bores.

6. A cylinder block in accordance with claim 5 wherein the cross-sectional area of said passages, taken in a direction normal to the axis of said bores, is substantially a constant throughout the length of said passages.

7. A device in accordance with claim 6 wherein said cross-sectional area of said passages substantially equals the cross-sectional area of said bores.

8. A hydraulic device comprising a pintle shaft having laterally open fluid supply ports, a block assembly having a central bearing aperture rotatably mounted over said shaft, said aperture being of a length in excess of, and overlying, said fluid supply ports of said shaft, said block including an axially enlarged boss portion adjacent said aperture and a generally cylindrical portion outwardly of said boss portion, the axial dimension of said cylindrical portion being less than that of said boss portion, a plurality of angularly spaced-apart cylinder bores extending radially from the outer periphery of said cylindrical portion toward said shaft, and fluid supply passages in said boss portion linking said aperture and said bores, the axial dimension of said passages at said aperture being greater than the axial dimension of said cylindrical portion of said block, the transverse dimension of said pas sages at said aperture being less than the diameters of said bores, said axial dimension of said passages becoming progressively shorter and said transverse dimension of said passages becoming progressively longer as said 1,983,261 12/ 1934 Zorzi 230-177 X passages approach said bores. 2,205,913 6/1940 Stacy 103-161 9. A device in accordance with claim 8 wherein said 2,273,468 2/1942 Ferris 103 161 passages are generally elliptical in section. 2,510,247 6/1950 p i 230 177 10. A device in accordance with claim 8 wherein the 5 3 034 5/1962 Sullivan et 1 103 1 1 cross-sectional area of said 1passages at any point along 3,044,412 7/1962 Orshansky 3 1 the length t ereof is genera y equa.

11. A device in accordance with claim 10 wherein the 3,211,105 10/1965 Bush et all n 130 161 cross-sectional area of said passages is generally equal to FOREIGN PATENTS the cross-sectional area of said bores.

583,396 12/1946 Great Britain. References Cited UNITED STATES PATENTS MARTIN P. SCHWADRON, Primary Examiner.

1,413,388 4/1922 Calhoun 230-177 15 I. C. COHEN, Assistant Examiner. 

1. IN A ROTARY HYDRAULIC DEVICE SUCH AS A PUMP OR MOTOR, A GENERALLY CYLINDRICAL PINTLE SHAFT HAVING AN AXIALLY ELONGAGED, RECESSED CIRCUMFERENCE PORTION DEFINING A FLUID SUPPLY AREA, A CYLINDER BLOCK HAVING A CENTRAL BEARING APERTURE ROTATABLY RECEIVED ON SAID SHAFT, THE AXIAL DIMENSION OF SAID APERTURE BEING IN EXCESS OF THE LENGTH OF SAID RECESSED PORTION, SAID APERTURE BEING DISPOSED IN REGISTRY WITH SAID AREA, A PLURALITY OF RADIALLY EXTENDING CYLINDER BORES FORMED IN SAID BLOCK, AND AXIALLY ELONGAGED FLUID PASSAGES EXTENDING BETWEEN SAID BORES AND SAID APERTURE, THE AXIAL DIMENSION OF SAID PASSAGES AT SAID APERTURE, BEING GREATER THAN THE DIAMETER OF SAID BORES, THE TRANSVERSE DIMENSION OF SAID PASSAGES AT SAID BORES BEING GREATER THAN THE TRANSVERSE DIMENSION OF SAID PASSAGES AT SAID APERTURE. 